The objective of this research is to develop methods by which NMR spectroscopy could be used to determine detailed structures of intercalative drug-DNA complexes. Such structures could be used with confidence as the basis for the design of potential new antitumor drugs. They would also increase our understanding of the biochemical and biophysical function of intercalation complexes. Previous work has shown that the use of deoxydinucleotides and oligodeoxynucleotides as models shows more immediate promise than a direct attack on DNA. We propose to use flourine substituted analogs to exploit the advantages of F19 NMR for studies of this type. Methodological problems will be worked out using a wide variety of ethidium bromide analogs. These methods will then be extended to important antitumor drugs currently in use in chemotherapy.